High si high al non-oriented silicon steel and method for producing the same

Abstract

The application discloses a high-Si high-Al non-oriented silicon steel and a production method thereof. The chemical composition adopts high Si of 2.0-3.5% and high Al of 1.0-2.0%, and further comprises Sn=0.01*Si+0.04*Al or Sb=0.01*Si+0.04*Al; a special protecting slag is used in a crystallizer in a continuous casting process; the heating temperature T1 of hot rolling is 1160-20*Si-10*Al, the final rolling temperature T2 is 880-20*Si-15*Al, and the coiling temperature T3 is 600+5*Si-30*Al; the soaking section temperature T4 of normalizing is 1050-30*Si-20*Al; and the pickling liquid of the first stage and the second stage both adopts an NH4HF2+HCl mixed solution, and the third stage adopts an H2O2+HCl mixed solution.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel smelting technology, and relates to a method for producing high-Si and high-Al non-oriented silicon steel, as well as a high-Si and high-Al non-oriented silicon steel prepared by the aforementioned method. Background Technology

[0002] Statistics show that electric motors account for 65% of the total electricity consumption in society. Therefore, improving the energy conversion efficiency of electric motors is of great significance for energy conservation and carbon reduction in the whole society. Non-oriented silicon steel is the core material of electric motors and generators that operate in a rotating magnetic field. It is required to have good magnetic properties, including low iron loss and high magnetic induction intensity, so as to effectively improve the energy conversion efficiency of electric motors and generators.

[0003] To impart good magnetic properties to non-oriented silicon steel, microalloying elements such as Si or Al are typically added to reduce iron loss. However, as the Si content increases, the steel's plasticity deteriorates, its rollability worsens dramatically, and when the Al content exceeds 1%, a composite oxide layer of Al2O3 and SiO2 easily forms on the strip surface during hot rolling. This composite oxide layer is difficult to remove, and its residue on the strip surface adversely affects the surface quality and magnetic properties of the finished product. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing high-Si, high-Al non-oriented silicon steel, in order to solve the technical problems in the prior art where the high Si and Al content in non-oriented silicon steel results in poor plasticity, and where a difficult-to-remove Al2O3 and SiO2 composite oxide layer is easily formed on the surface of the strip during hot rolling, thereby affecting the surface quality and electromagnetic properties of the non-oriented silicon steel; and the purpose of this invention is also to provide a high-Si, high-Al non-oriented silicon steel prepared by the aforementioned method.

[0005] To achieve one of the above objectives, one embodiment of the present invention provides a method for producing high-Si, high-Al non-oriented silicon steel, comprising the sequentially performed processes of smelting, continuous casting, hot rolling, normalizing, pickling, cold rolling, annealing, and coating.

[0006] In the smelting process, the chemical composition of the final molten steel obtained by smelting, by mass percentage, includes: C≤0.0025%, Si 2.0~3.5%, Al 1.0~2.0%, Mn 0.2~0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sn or Sb, with the remainder being Fe and unavoidable impurities. The Sn content is 0.01×Si+0.04×Al, the Sb content is 0.01×Si+0.04×Al, and C+S+O+N≤0.007%.

[0007] In the continuous casting process, a special protective slag is used in the continuous casting crystallizer. The chemical composition of the protective slag, by mass percentage, includes: SiO2 28-36%, MgO≤5%, CaO 16-24%, Fe2O3≤5%, Al2O3≤5%, Na2O 13-15%, CaF 8-14%, Li2O 1.1-1.5%, B2O3 4.5-5.5%, TC≤1.5%, and exothermic agent 1.9-2.1%.

[0008] In the hot rolling process, the continuously cast billet obtained from the continuous casting process is sequentially heated, rough rolled, finish rolled, and coiled to obtain a hot rolled coil. The heating temperature T1 = 1160 - 20 × [Si] - 10 × [Al], the heating time is 160 to 180 min, the final rolling temperature T2 = 880 - 20 × [Si] - 15 × [Al], and the coiling temperature T3 = 600 + 5 × [Si] - 30 × [Al].

[0009] In the normalizing process, the uncoiled strip steel is heated with an open flame that does not oxidize. The heating rate of the strip steel is 30-40℃ / s. The temperature of the soaking zone is T4 = 1050-30×[Si]-20×[Al]. The holding time of the soaking zone is 40-70s. Then it is slowly cooled to 700℃ at a cooling rate of 10℃ / s. Then it is rapidly cooled to room temperature at a cooling rate of 30℃ / s.

[0010] In the shot blasting and pickling process, pickling is carried out in three stages. The first stage uses a mixed solution of NH4HF2 and HCl, with NH4HF2 concentration of 60-80 g / L and HCl concentration of 150-200 g / L. The second stage uses the same mixed solution with NH4HF2 and HCl, with NH4HF2 concentration of 80-100 g / L and HCl concentration of 200-250 g / L. The third stage uses a mixed solution of H2O2 and HCl, with H2O2 concentration of 30-50 g / L and HCl concentration of 100-120 g / L. The pickling time t and pickling temperature T5 for each of the three stages correspond one-to-one and satisfy the following conditions:

[0011]

[0012] Where B = -0.01 × [NH4HF2] 2 +2×[HCl]-75, where t is in seconds and temperature is in degrees Celsius.

[0013] As a further improvement of one embodiment of the present invention, in the continuous casting process, the exothermic agent is a calcium-silicon alloy, wherein the mass percentage of Ca is 40% and the mass percentage of Si is 60%.

[0014] As a further improvement of one embodiment of the present invention, in the continuous casting process, the binary basicity of the protective slag is 0.61 to 0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

[0015] As a further improvement of one embodiment of the present invention, in the continuous casting process, electromagnetic stirring is used in the secondary cooling zone, with a stirring current of 400A, a stirring frequency of 8Hz, and a continuous casting speed of 1.2±0.1m / min.

[0016] As a further improvement of one embodiment of the present invention, in the cold rolling process, a 20-roll single stand is used to perform reciprocating cold rolling on the hot-rolled strip after the pickling process to obtain a cold-rolled coil with a thickness of 0.2 to 0.4 mm. The reduction rate of the first pass is controlled at 25 to 35%, and the total reduction rate is controlled at 80 to 90%.

[0017] As a further improvement of one embodiment of the present invention, in the annealing process, the cold-rolled coil obtained in the cold rolling process is subjected to high-temperature annealing under a pure N2 protective atmosphere. The annealing temperature T6 = 900 + 30 × [Si] + 20 × [Al], in °C, and the annealing time is 80 to 100 s. The steel coil after high-temperature annealing is controlled to complete sufficient recrystallization, and the average grain size is 80 to 120 μm.

[0018] As a further improvement of one embodiment of the present invention, in the annealing process, the steel coil after high-temperature annealing is cooled, and the cooling rate before cooling to 400-550°C is controlled to be ≤10°C / s.

[0019] As a further improvement of one embodiment of the present invention, in the hot rolling process, the continuously cast billet is fed into a heating furnace for heating, the furnace temperature of the continuously cast billet is 500-600°C, the roughing rolling is carried out in a double-stand 6-pass roughing rolling, including 1 pass roughing rolling in the first stand and 5 passes roughing rolling in the second stand, the finishing rolling is carried out in a seven-stand finishing mill 7-pass finishing rolling, the total reduction rate of finishing rolling is controlled to be 93-94%, and the thickness of the hot-rolled coil is 1.8-2.0 mm.

[0020] To achieve the above-mentioned objective, one embodiment of the present invention also provides a high-Si, high-Al non-oriented silicon steel, which is prepared by the production method of high-Si, high-Al non-oriented silicon steel described above.

[0021] As a further improvement to one embodiment of the present invention, the iron loss P of the high-Si, high-Al non-oriented silicon steel is... 1.5 / 50 ≤2.5W / kg, iron loss P 1.0 / 400 ≤17W / kg, iron loss P 1.0 / 800 ≤25W / kg, magnetic induction B 2500 ≥1.58T, B 5000 ≥1.63T.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) Based on the conventional composition of non-oriented silicon steel, this invention increases the content of Si and Al, which not only improves the resistivity of non-oriented silicon steel and reduces iron loss, but also, through the design of the chemical composition scheme of the mold flux in the continuous casting process, inhibits the redox reaction between Al in the molten steel and SiO2 in the flux, improves the lubrication and heat transfer effect of the flux, improves the surface quality of the continuous casting billet, and solves the problem of easy cracking on the surface of high-Al silicon steel continuous casting billets; furthermore, by controlling the temperature at each stage during hot rolling, the formation of the Al2O3 and SiO2 composite oxide layer on the strip surface can be reduced, thereby controlling the type and thickness of the oxide scale; combined with the improvement of the pickling process, through Using NH4HF2+HCl pickling solution to replace the traditional HCl pickling process, and by controlling the concentration of NH4HF2+HCl, pickling temperature, and pickling time, the Al2O3 and SiO2 oxide layers on the surface of hot-rolled strip steel can be thoroughly cleaned. Moreover, by adding H2O2 during the third pickling stage, intergranular corrosion on the surface of the steel coil is avoided. Furthermore, by adding microalloying elements Sn or Sb and limiting their content in relation to Al and Si content, the principle that Sn or Sb easily accumulates on the surface of the strip steel can be utilized to prevent the formation of dense AlN during the annealing process. This promotes the optimization of the microstructure of the final non-oriented silicon steel matrix, enabling it to obtain excellent magnetic properties and meet the production requirements of wound iron cores.

[0024] (2) The high-Si, high-Al non-oriented silicon steel prepared by the above production method has a low iron loss P 1.5 / 50 ≤2.5W / kg, iron loss P 1.0 / 400 ≤17W / kg, iron loss P 1.0 / 800 ≤25W / kg, magnetic induction B 2500 ≥1.58T, B 5000 With a strength of ≥1.63T, it exhibits excellent magnetic induction performance and superior surface quality, free from surface defects. When applied to products such as motors, its electromagnetic performance is qualified, meeting the energy efficiency requirements of these products. Detailed Implementation

[0025] The present invention will now be described in detail with reference to specific embodiments. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0026] One embodiment of the present invention provides a method for producing high-Si, high-Al non-oriented silicon steel, and a high-Si, high-Al non-oriented silicon steel obtained by the method.

[0027] In this embodiment, the chemical composition design scheme of the high-Si, high-Al non-oriented silicon steel is as follows, and its chemical composition, by mass percentage, includes: C≤0.0025%, Si 2.0~3.5%, Al 1.0~2.0%, Mn0.2~0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sn or Sb, with the remainder being Fe and unavoidable impurities, wherein Sn=0.01×Si+0.04×Al, Sb=0.01×Si+0.04×Al, and C+S+O+N≤0.007%.

[0028] In other words, the above chemical composition design scheme includes either Sn or Sb.

[0029] Specifically, the chemical composition of the high-Si, high-Al non-oriented silicon steel of the present invention, by mass percentage, includes: C≤0.0025%, Si 2.0~3.5%, Al 1.0~2.0%, Mn 0.2~0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sn=0.01×Si+0.04×Al, with the remainder being Fe and unavoidable impurities, and C+S+O+N≤0.007%.

[0030] Alternatively, the chemical composition of the high-Si, high-Al non-oriented silicon steel of the present invention, by mass percentage, includes: C≤0.0025%, Si 2.0~3.5%, Al 1.0~2.0%, Mn 0.2~0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sb=0.01×Si+0.04×Al, with the remainder being Fe and unavoidable impurities, and C+S+O+N≤0.007%.

[0031] Based on the above chemical composition design, the resistivity of non-oriented silicon steel can be improved and iron loss reduced by adding Si, Al, and Mn elements. However, with the increase of the alloying element Si content, the toughness of the steel decreases sharply, making it prone to strip breakage during cold rolling. Furthermore, a difficult-to-remove Al2O3 and SiO2 composite oxide layer is easily formed on the surface of the strip. This invention increases the Si and Al content based on the conventional composition of non-oriented silicon steel. On the one hand, this can improve the resistivity of non-oriented silicon steel and reduce iron loss. On the other hand, by controlling each process in the subsequent production method, the problems of cold rolling strip breakage and the easy formation and difficulty in removing the Al2O3 and SiO2 composite oxide layer can be solved. Furthermore, by adding microalloying elements Sn or Sb and limiting their content in relation to Al and Si content, the principle that Sn or Sb easily accumulates on the surface of the strip can be utilized to avoid the formation of dense AlN in the strip during annealing. This promotes the optimization of the microstructure of the final non-oriented silicon steel matrix, enabling it to obtain excellent elongation and electromagnetic properties, meeting the production requirements of wound iron cores.

[0032] The production method of the high-Si, high-Al non-oriented silicon steel is described in detail below, including the sequential processes of smelting, continuous casting, hot rolling, normalizing, pickling, cold rolling, annealing, and coating.

[0033] (1) Smelting

[0034] The chemical composition of the final molten steel obtained by smelting, by mass percentage, includes: C≤0.0025%, Si2.0~3.5%, Al1.0~2.0%, Mn0.2~0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sn or Sb, with the remainder being Fe and unavoidable impurities. Among these, the Sn content is 0.01×Si+0.04×Al, the Sb content is 0.01×Si+0.04×Al, and C+S+O+N≤0.007%.

[0035] In other words, the steel smelting process is carried out according to the above-mentioned chemical composition design scheme for high-Si and high-Al non-oriented silicon steel, so that the chemical composition of the final molten steel is exactly the same as that of the final high-Si and high-Al non-oriented silicon steel.

[0036] Specifically, the steel smelting process includes the following steps performed sequentially:

[0037] a. Desulfurization of molten iron (KR)

[0038] The molten iron is desulfurized in the KR desulfurization unit, and the slag removal rate is controlled to be >95%, and the sulfur content in the molten iron is ≤0.001% when it leaves the station.

[0039] b. Converter smelting

[0040] The desulfurized molten iron is fed into a converter and mixed with scrap steel to form molten steel, which is then dephosphorized and desiliconized until the S ≤ 0.002%, P ≤ 0.02%, and N ≤ 0.0025% content is reached before tapping. All scrap steel used is recycled non-oriented silicon steel, and its weight accounts for 12-16% of the total converter charge.

[0041] c.RH Vacuum Refining

[0042] The RH vacuum circulation degassing equipment is used to perform vacuum decarburization, deoxidation, alloying and inclusion removal on molten steel after converter smelting.

[0043] In the RH vacuum refining process, oxygen (O) from the converter steel is used for decarburization, followed by deoxidation using silicon (Si). During alloying, Si is added first, then Al, and finally Sn or Sb is added based on the actual Si / Al content. Finally, a net circulation process is performed under vacuum conditions, which effectively removes inclusions from the molten steel.

[0044] (2) Continuous casting

[0045] The molten steel obtained from the steel smelting process is continuously cast into a continuous casting billet with a thickness of 220mm using a continuous casting equipment. The chemical composition of the resulting continuous casting billet is consistent with the chemical composition of the molten steel obtained in the final steel smelting process, and is also completely identical to the chemical composition of the high-Al non-oriented silicon steel wound core that is finally prepared.

[0046] The continuous casting mold uses a special protective slag. The chemical composition of the protective slag, by mass percentage, includes: SiO2 28–36%, MgO ≤5%, CaO 16–24%, Fe2O3 ≤5%, Al2O3 ≤5%, Na2O 13–15%, CaF 8–14%, Li2O 1.1–1.5%, B2O3 4.5–5.5%, TC ≤1.5%, and exothermic agent 1.9–2.1%. Through the design of the protective slag composition, the addition of Li2O, B2O3, and the exothermic agent not only inhibits the redox reaction between Al in the molten steel and SiO2 in the protective slag during continuous casting, but also improves heat transfer and provides lubrication, preventing defects such as cracks on the surface of the continuously cast billet.

[0047] Preferably, the heating agent is a calcium-silicon alloy, wherein the mass percentage of Ca is 40% and the mass percentage of Si is 60%.

[0048] Preferably, the binary basicity of the protective slag is 0.61 to 0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

[0049] Preferably, during the continuous casting process, electromagnetic stirring is used in the secondary cooling zone, with a stirring current of 400A, a stirring frequency of 8Hz, and a continuous casting speed of 1.2±0.1m / min.

[0050] (3) Hot rolling

[0051] The continuously cast billet obtained from the continuous casting process is sequentially heated, rough rolled, finish rolled, and coiled to obtain a hot-rolled coil. Among them, the heating temperature T1 = 1160 - 20 × [Si] - 10 × [Al], the heating time is 160 to 180 min, the initial rolling temperature of finish rolling is 910 to 960℃, the final rolling temperature of finish rolling is T2 = 880 - 20 × [Si] - 15 × [Al], and the coiling temperature is T3 = 600 + 5 × [Si] - 30 × [Al].

[0052] Wherein, [Si] represents the mass percentage of Si element in the continuously cast billet, and [Al] represents the mass percentage of Al element in the continuously cast billet. For example, if the Si element content in the continuously cast billet is 2.2%, then [Si] = 2.2. The same applies in the following text.

[0053] Thus, by controlling the Si and Al element content in the chemical composition and controlling the temperature of each step in the hot rolling process, the type and thickness of the Al2O3 and SiO2 composite oxide can be controlled.

[0054] Preferably, the continuously cast billet is fed into a heating furnace for heating, and the furnace temperature of the continuously cast billet is 500-600°C. The roughing rolling is carried out in a double-stand 6-pass roughing rolling, including 1 pass roughing rolling in the first stand and 5 passes roughing rolling in the second stand. The finishing rolling is carried out in a seven-stand finishing mill for 7 passes, and the total reduction rate of the finishing rolling is controlled to be 93-94%. The thickness of the hot-rolled coil is 1.8-2.0 mm.

[0055] (4) Normalization

[0056] The hot-rolled coil is subjected to normalization treatment. Specifically, the strip steel after uncoiling is heated with an open flame without oxidation. The heating rate of the strip steel is 30-40℃ / s. The temperature of the soaking zone is T4 = 1050-30×[Si]-20×[Al]. The holding time of the soaking zone is 40-70s. Then it is slowly cooled to 700℃ at a cooling rate of 10℃ / s. Then it is rapidly cooled to room temperature at a cooling rate of 30℃ / s.

[0057] By controlling the heating and cooling during the normalizing process, and by controlling the temperature of the soaking zone during normalizing in conjunction with the Si and Al content in the non-oriented silicon steel, the non-uniformity of the microstructure and the magnetic properties of the hot-rolled non-oriented silicon steel coil can be improved, giving it a good texture and improving the inconsistency of magnetic properties at the beginning, middle and end of the process.

[0058] (5) Pickling

[0059] First, the steel coils after the normalizing process are shot blasted to break the oxide scale on their surface, and then pickled.

[0060] Pickling is carried out in three stages. The first stage uses a mixed solution of NH4HF2 and HCl, with NH4HF2 concentrations of 60–80 g / L and HCl concentrations of 150–200 g / L. The second stage uses the same solution, with NH4HF2 concentrations of 80–100 g / L and HCl concentrations of 200–250 g / L. The third stage uses a mixed solution of H2O2 and HCl, with H2O2 concentrations of 30–50 g / L and HCl concentrations of 100–120 g / L. The pickling time t and pickling temperature T5 for each of the three stages correspond one-to-one and satisfy the following conditions:

[0061]

[0062] Where B = -0.01 × [NH4HF2] 2 +2×[HCl]-75, where t is in seconds and temperature is in degrees Celsius.

[0063] [NH4HF2] represents the concentration of NH4HF2 in the mixed solution, and [HCl] represents the concentration of HCl in the mixed solution. For example, when the concentration of NH4HF2 is 80 g / L, [NH4HF2] = 80; in the third stage, since no NH4HF2 is added, [NH4HF2] = 0.

[0064] By using the above pickling method, the NH4HF2+HCl mixed solution is used to replace the traditional HCl pickling process in the first two stages, and the concentrations of NH4HF2 and HCl are controlled. Furthermore, the pickling time and temperature of each of the three stages are limited by the concentrations of NH4HF2, HCl, Si content, and Al content. This can effectively clean the Al2O3 and SiO2 composite oxide layer on the surface of hot-rolled coils, solving the problem of the difficulty in removing the Al2O3 and SiO2 composite oxide layer on the surface of high-Si and high-Al steel. In the third stage of pickling, the H2O2+HCl mixed solution is used, which can prevent intergranular corrosion from occurring on the surface of hot-rolled coils.

[0065] (6) Cold rolling

[0066] The preferred method is to use a 20-roll single stand to perform reciprocating cold rolling on the hot-rolled strip after the pickling process to obtain a cold-rolled coil with a thickness of 0.2 to 0.4 mm. The reduction rate of the first pass is controlled at 25 to 35%, and the total reduction rate is controlled at 80 to 90%.

[0067] (7) Annealing

[0068] The cold-rolled coil is fed into an annealing furnace for high-temperature annealing, followed by cooling. This invention utilizes the principle that Sn or Sb readily accumulates on the surface of the strip, preventing the formation of dense AlN during annealing. This promotes microstructure optimization in the final non-oriented silicon steel matrix, resulting in excellent magnetic properties that meet the production requirements of wound cores.

[0069] Preferably, the cold-rolled coil obtained from the cold rolling process is subjected to high-temperature annealing under a pure N2 protective atmosphere. The annealing temperature T6 = 900 + 30 × [Si] + 20 × [Al], in °C, and the annealing time is 80 to 100 s. The steel coil after high-temperature annealing is controlled to complete sufficient recrystallization and the average grain size is 80 to 120 μm.

[0070] Preferably, during cooling, the cooling rate is controlled to be ≤10℃ / s before cooling to 400-550℃.

[0071] (8) Coating

[0072] An insulating layer is uniformly coated on the upper and lower surfaces of the annealed non-oriented silicon steel strip to improve its insulation performance, resulting in a high-Si, high-Al non-oriented silicon steel product.

[0073] The specific operations of the coating can be achieved using existing feasible coating and finishing technologies, and will not be elaborated here.

[0074] The production method of this invention, based on a high-Si, high-Al chemical composition design, adds microalloying elements Sn or Sb and limits their content in relation to Al and Si content. This not only prevents the formation of dense AlN in the strip steel during annealing, resulting in high cleanliness, low iron loss, and high magnetic flux density in the prepared non-oriented silicon steel, but also, through the design of the chemical composition of the mold flux in the continuous casting process, inhibits the redox reaction between Al in the molten steel and SiO2 in the mold flux, improving the lubrication and heat transfer effects of the mold flux, thus improving the surface quality of the continuously cast billet and solving the problem of… High-Al silicon steel continuously cast billets are prone to surface cracking. Further, by controlling the temperature at each stage of hot rolling, the formation of the Al2O3 and SiO2 composite oxide layer on the surface of the strip can be reduced. Combined with the improvement of the pickling process, the traditional HCl pickling process is replaced by NH4HF2+HCl pickling solution. By controlling the concentration of NH4HF2+HCl, pickling temperature and pickling time, the Al2O3 and SiO2 oxide layers on the surface of hot-rolled strip can be cleaned. Moreover, by adding H2O2 in the third pickling stage, intergranular corrosion on the surface of the steel coil is avoided.

[0075] An embodiment of the present invention also provides a high-Si, high-Al non-oriented silicon steel, prepared by the above-described production method. The thickness of the high-Si, high-Al non-oriented silicon steel is 0.2–0.4 mm, and as mentioned above, its chemical composition, by mass percentage, includes: C ≤ 0.0025%, Si 2.0–3.5%, Al 1.0–2.0%, Mn 0.2–0.4%, Nb ≤ 0.002%, V ≤ 0.002%, Ti ≤ 0.002%, Ni ≤ 0.03%, Cr ≤ 0.03%, Cu ≤ 0.01%, N ≤ 0.002%, P ≤ 0.01%, S ≤ 0.0015%, and Sn or Sb, with the remainder being Fe and unavoidable impurities. The Sn content is 0.01 × Si + 0.04 × Al, the Sb content is 0.01 × Si + 0.04 × Al, and C + S + O + N ≤ 0.007%.

[0076] Testing revealed that the high-Si, high-Al non-oriented silicon steel produced using the above method exhibited low iron loss (P0.05). 1.5 / 50 ≤2.5W / kg, iron loss P 1.0 / 400 ≤17W / kg, iron loss P 1.0 / 800 ≤25W / kg, magnetic induction B 2500 ≥1.58T, B 5000 With a strength of ≥1.63T, it exhibits excellent magnetic induction performance and elongation that meets the plastic deformation requirements of the wound iron core during the winding process. The winding process is crack-free, and the surface quality is excellent with no surface defects. When applied to products such as motors, its electromagnetic performance is qualified and can meet the energy efficiency requirements of these products.

[0077] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0078] The beneficial effects of the present invention will be further illustrated by the following three embodiments. Of course, these three embodiments are only a part of the many variations contained in the present invention, and not all of them.

[0079] The three embodiments each provide a high-Si, high-Al non-oriented silicon steel. The chemical composition of the molten steel, continuously cast billet, and the final high-Si, high-Al non-oriented silicon steel obtained in each embodiment is the same. The specific chemical compositions of the three embodiments are shown in Table 1. Furthermore, apart from the chemical elements shown in Table 1, the chemical compositions of the three embodiments contain the following components: C≤0.0025%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, C+S+O+N≤0.007%, with the remainder being Fe and unavoidable impurities.

[0080] Table 1

[0081]

[0082]

[0083] Example 1

[0084] The production method of high-Si, high-Al non-oriented silicon steel includes the following steps performed in sequence:

[0085] (1) Smelting

[0086] The chemical composition of the final molten steel obtained from smelting is as described above; please refer to Table 1 for details.

[0087] Specifically, the steel smelting process includes the following steps performed sequentially:

[0088] a. Desulfurization of molten iron (KR)

[0089] The molten iron was desulfurized in the KR desulfurization unit, and the slag removal rate was controlled at 97%. The sulfur content in the molten iron was 0.0008% when it left the station.

[0090] b. Converter smelting

[0091] The desulfurized molten iron is fed into a converter and mixed with scrap steel to form molten steel, which is then dephosphorized and desiliconized until the S content in the molten steel is 0.0018%, the P content is 0.02%, and the N content is 0.0016%. The scrap steel used is all recycled non-oriented silicon steel, and its weight accounts for 15% of the total converter charge.

[0092] c.RH Vacuum Refining

[0093] An RH vacuum circulation degassing system is used to perform vacuum decarburization, deoxidation, alloying, and inclusion removal treatments on molten steel after converter smelting. During the RH vacuum refining process, oxygen (O) from the converter tapping is used for decarburization, followed by deoxidation using silicon (Si). In the alloying process, Si is added first, followed by Al, and then Sn or Sb is added based on the actual Si / Al content. Finally, a net circulation process is performed under vacuum conditions to effectively remove inclusions from the molten steel.

[0094] (2) Continuous casting

[0095] Specifically, the molten steel obtained from the steelmaking process is continuously cast into a continuous casting billet with a thickness of 220 mm using a continuous casting equipment. The chemical composition of the continuous casting billet is as described above, please refer to Table 1 for details.

[0096] The continuous casting crystallizer uses a special protective slag. The chemical composition of the protective slag, by mass percentage, includes: SiO2 28–36%, MgO ≤5%, CaO 16–24%, Fe2O3 ≤5%, Al2O3 ≤5%, Na2O 13–15%, CaF 8–14%, Li2O 1.1–1.5%, B2O3 4.5–5.5%, TC ≤1.5%, and exothermic agent 1.9–2.1%. The exothermic agent is a calcium-silicon alloy, with Ca accounting for 40% by mass and Si accounting for 60% by mass. The binary basicity of the protective slag is 0.61–0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

[0097] During the continuous casting process, electromagnetic stirring is used in the secondary cooling zone with a stirring current of 400A, a stirring frequency of 8Hz, and a continuous casting speed of 1.2±0.1m / min.

[0098] (3) Hot rolling

[0099] The continuously cast billet obtained from the continuous casting process is first fed into a heating furnace for heating. The furnace entry temperature of the billet is 500-600℃, the heating temperature T1 = 1101℃, and the heating time is 160-180 minutes. Then, it is fed into a two-stand roughing mill for 6 passes of roughing rolling. Specifically, after 1 pass of roughing rolling on the first stand, it is fed into the second stand for 5 passes of roughing rolling. Then, it is fed into a seven-stand finishing mill for 7 passes of finishing rolling. The starting rolling temperature of finishing rolling is 920℃, the finishing rolling temperature is T2 = 812℃, and the total reduction rate of finishing rolling is 93%. Finally, a hot-rolled coil with a thickness of 2.0mm is obtained, and the coiling temperature is T3 = 553℃.

[0100] (4) Normalization

[0101] The uncoiled strip steel is heated using an open flame without oxidation. The heating rate of the strip steel is 30-40℃ / s. The temperature of the soaking zone is T4 = 952℃. The holding time of the soaking zone is 70s. Then it is slowly cooled to 700℃ at a cooling rate of 10℃ / s. Then it is rapidly cooled to room temperature at a cooling rate of 30℃ / s.

[0102] (5) Pickling

[0103] First, the steel coils after the normalizing process are shot-blasted to break the oxide scale on their surface, followed by pickling. Pickling is carried out in three stages. The first stage uses a mixed solution of NH4HF2 and HCl, with an NH4HF2 concentration of 60 g / L and an HCl concentration of 190 g / L. The pickling temperature T5 is 90℃, and the pickling time t is 25 s. The second stage uses a mixed solution of NH4HF2 and HCl, with an NH4HF2 concentration of 95 g / L and an HCl concentration of 240 g / L. The pickling temperature T5 is 95℃, and the pickling time t is 20 s. The third stage uses a mixed solution of H2O2 and HCl, with an H2O2 concentration of 30 g / L and an HCl concentration of 100 g / L. The pickling temperature T5 is 95℃, and the pickling time t is 50 s.

[0104] (6) Cold rolling

[0105] A 20-roll single stand is used to perform reciprocating cold rolling on hot-rolled strip after pickling to obtain a cold-rolled coil with a thickness of 0.2 mm. The reduction rate of the first pass is controlled at 25%, and the total reduction rate is controlled at 90%.

[0106] (7) Annealing

[0107] The cold-rolled coils obtained from the cold rolling process are sent to an annealing furnace and subjected to high-temperature annealing under a pure N2 protective atmosphere. The annealing temperature is T6 = 998℃ and the annealing time is 80s. The steel coils after high-temperature annealing are controlled to complete full recrystallization and the average grain size is 85μm. During cooling, the cooling rate is controlled to be ≤10℃ / s before cooling to 400-550℃.

[0108] (8) Coating

[0109] An insulating layer is uniformly coated on the upper and lower surfaces of the annealed non-oriented silicon steel strip and then finished to obtain a high-Si, high-Al non-oriented silicon steel product.

[0110] The non-oriented silicon steel products from the three embodiments were tested to obtain their iron loss P. 1.5 / 50 Iron loss P 1.0 / 400 Iron loss P 1.0 / 800 Magnetic induction intensity B 2500 and magnetic induction intensity B 5000 The data is shown in Table 2.

[0111] Example 2

[0112] The production method of high-Si, high-Al non-oriented silicon steel includes the following steps performed in sequence:

[0113] (1) Smelting

[0114] The chemical composition of the final molten steel obtained from smelting is as described above; please refer to Table 1 for details.

[0115] Specifically, the steel smelting process includes the following steps performed sequentially:

[0116] a. Desulfurization of molten iron (KR)

[0117] The molten iron is desulfurized in the KR desulfurization unit, with the slag removal rate controlled at 98%, and the sulfur content in the molten iron is 0.0009% when it leaves the station.

[0118] b. Converter smelting

[0119] The desulfurized molten iron is fed into a converter and mixed with scrap steel to form molten steel, which is then dephosphorized and desiliconized until the S content in the molten steel is 0.0016%, the P content is 0.017%, and the N content is 0.0014%. The scrap steel used is all recycled non-oriented silicon steel, and its weight accounts for 12% of the total converter charge.

[0120] c.RH Vacuum Refining

[0121] An RH vacuum circulation degassing system is used to perform vacuum decarburization, deoxidation, alloying, and inclusion removal treatments on molten steel after converter smelting. During the RH vacuum refining process, oxygen (O) from the converter tapping is used for decarburization, followed by deoxidation using silicon (Si). In the alloying process, Si is added first, followed by Al, and then Sn or Sb is added based on the actual Si / Al content. Finally, a net circulation process is performed under vacuum conditions to effectively remove inclusions from the molten steel.

[0122] (2) Continuous casting

[0123] Specifically, the molten steel obtained from the steelmaking process is continuously cast into a continuous casting billet with a thickness of 220 mm using a continuous casting equipment. The chemical composition of the continuous casting billet is as described above, please refer to Table 1 for details.

[0124] The continuous casting crystallizer uses a special protective slag. The chemical composition of the protective slag, by mass percentage, includes: SiO2 28–36%, MgO ≤5%, CaO 16–24%, Fe2O3 ≤5%, Al2O3 ≤5%, Na2O 13–15%, CaF 8–14%, Li2O 1.1–1.5%, B2O3 4.5–5.5%, TC ≤1.5%, and exothermic agent 1.9–2.1%. The exothermic agent is a calcium-silicon alloy, with Ca accounting for 40% by mass and Si accounting for 60% by mass. The binary basicity of the protective slag is 0.61–0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

[0125] During the continuous casting process, electromagnetic stirring is used in the secondary cooling zone with a stirring current of 400A, a stirring frequency of 8Hz, and a continuous casting speed of 1.2±0.1m / min.

[0126] (3) Hot rolling

[0127] The continuously cast billet obtained from the continuous casting process is first fed into a heating furnace for heating. The furnace entry temperature of the billet is 500-600℃, the heating temperature T1 = 1089℃, and the heating time is 160-180 minutes. Then, it is fed into a two-stand roughing mill for 6 passes of roughing rolling. Specifically, after 1 pass of roughing rolling on the first stand, it is fed into the second stand for 5 passes of roughing rolling. Then, it is fed into a seven-stand finishing mill for 7 passes of finishing rolling. The starting rolling temperature of finishing rolling is 910℃, the finishing rolling temperature is T2 = 802℃, and the total reduction rate of finishing rolling is 94%. Finally, a hot-rolled coil with a thickness of 1.9mm is obtained, and the coiling temperature is T3 = 563℃.

[0128] (4) Normalization

[0129] The uncoiled strip steel is heated using an open flame without oxidation. The heating rate of the strip steel is 30-40℃ / s. The temperature of the soaking zone is T4 = 936℃. The holding time of the soaking zone is 50s. Then it is slowly cooled to 700℃ at a cooling rate of 10℃ / s. Then it is rapidly cooled to room temperature at a cooling rate of 30℃ / s.

[0130] (5) Pickling

[0131] First, the steel coils after the normalizing process are shot-blasted to break the oxide scale on their surface, followed by pickling. Pickling is carried out in three stages. The first stage uses a mixed solution of NH4HF2 and HCl, with NH4HF2 concentration of 70 g / L and HCl concentration of 170 g / L, pickling temperature T5 of 95℃, and pickling time t of 32 s. The second stage uses a mixed solution of NH4HF2 and HCl, with NH4HF2 concentration of 90 g / L and HCl concentration of 220 g / L, pickling temperature T5 of 92℃, and pickling time t of 25 s. The third stage uses a mixed solution of H2O2 and HCl, with H2O2 concentration of 40 g / L and HCl concentration of 110 g / L, pickling temperature T5 of 92℃, and pickling time t of 50 s.

[0132] (6) Cold rolling

[0133] A 20-roll single-stand reciprocating cold rolling process was used to process the hot-rolled strip after pickling to obtain a cold-rolled coil with a thickness of 0.25 mm. The reduction rate of the first pass was controlled at 30%, and the total reduction rate was controlled at 86.8%.

[0134] (7) Annealing

[0135] The cold-rolled coils obtained from the cold rolling process are sent to an annealing furnace and subjected to high-temperature annealing under a pure N2 protective atmosphere. The annealing temperature is T6 = 1014℃ and the annealing time is 90s. The steel coils after high-temperature annealing are controlled to complete full recrystallization and the average grain size is 95μm. During cooling, the cooling rate is controlled to be ≤10℃ / s before cooling to 400~550℃.

[0136] (8) Coating

[0137] An insulating layer is uniformly coated on the upper and lower surfaces of the annealed non-oriented silicon steel strip and then finished to obtain a high-Si, high-Al non-oriented silicon steel product.

[0138] The non-oriented silicon steel products from the three embodiments were tested to obtain their iron loss P. 1.5 / 50 Iron loss P 1.0 / 400 Iron loss P 1.0 / 800 Magnetic induction intensity B 2500 and magnetic induction intensity B 5000 The data is shown in Table 2.

[0139] Example 3

[0140] The production method of high-Si, high-Al non-oriented silicon steel includes the following steps performed in sequence:

[0141] (1) Smelting

[0142] The chemical composition of the final molten steel obtained from smelting is as described above; please refer to Table 1 for details.

[0143] Specifically, the steel smelting process includes the following steps performed sequentially:

[0144] a. Desulfurization of molten iron (KR)

[0145] The molten iron is desulfurized in the KR desulfurization unit, and the slag removal rate is controlled at 98%. The sulfur content in the molten iron when it leaves the station is 0.0008%.

[0146] b. Converter smelting

[0147] The desulfurized molten iron is fed into a converter and mixed with scrap steel to form molten steel, which is then dephosphorized and desiliconized until the S content in the molten steel is 0.0018%, the P content is 0.02%, and the N content is 0.0016%. The scrap steel used is all recycled non-oriented silicon steel, and its weight accounts for 16% of the total converter charge.

[0148] c.RH Vacuum Refining

[0149] An RH vacuum circulation degassing system is used to perform vacuum decarburization, deoxidation, alloying, and inclusion removal treatments on molten steel after converter smelting. During the RH vacuum refining process, oxygen (O) from the converter tapping is used for decarburization, followed by deoxidation using silicon (Si). In the alloying process, Si is added first, followed by Al, and then Sn or Sb is added based on the actual Si / Al content. Finally, a net circulation process is performed under vacuum conditions to effectively remove inclusions from the molten steel.

[0150] (2) Continuous casting

[0151] Specifically, the molten steel obtained from the steelmaking process is continuously cast into a continuous casting billet with a thickness of 220 mm using a continuous casting equipment. The chemical composition of the continuous casting billet is as described above, please refer to Table 1 for details.

[0152] The continuous casting crystallizer uses a special protective slag. The chemical composition of the protective slag, by mass percentage, includes: SiO2 28–36%, MgO ≤5%, CaO 16–24%, Fe2O3 ≤5%, Al2O3 ≤5%, Na2O 13–15%, CaF 8–14%, Li2O 1.1–1.5%, B2O3 4.5–5.5%, TC ≤1.5%, and exothermic agent 1.9–2.1%. The exothermic agent is a calcium-silicon alloy, with Ca accounting for 40% by mass and Si accounting for 60% by mass. The binary basicity of the protective slag is 0.61–0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

[0153] During the continuous casting process, electromagnetic stirring is used in the secondary cooling zone with a stirring current of 400A, a stirring frequency of 8Hz, and a continuous casting speed of 1.2±0.1m / min.

[0154] (3) Hot rolling

[0155] The continuously cast billet obtained from the continuous casting process is first fed into a heating furnace for heating. The furnace entry temperature of the billet is 500-600℃, the heating temperature T1 = 1082℃, and the heating time is 160-180 minutes. Then, it is fed into a two-stand roughing mill for 6 passes of roughing rolling. Specifically, after 1 pass of roughing rolling on the first stand, it is fed into the second stand for 5 passes of roughing rolling. Then, it is fed into a seven-stand finishing mill for 7 passes of finishing rolling. The starting rolling temperature of finishing rolling is 910℃, the finishing rolling temperature T2 = 797℃, and the total reduction rate of finishing rolling is 94%. Finally, a hot-rolled coil with a thickness of 1.8mm is obtained, and the coiling temperature is T3 = 587℃.

[0156] (4) Normalization

[0157] The uncoiled strip steel is heated using an open flame without oxidation. The heating rate of the strip steel is 30-40℃ / s. The temperature of the soaking zone is T4 = 928℃. The holding time of the soaking zone is 40s. Then it is slowly cooled to 700℃ at a cooling rate of 10℃ / s. Then it is rapidly cooled to room temperature at a cooling rate of 30℃ / s.

[0158] (5) Pickling

[0159] First, the steel coils after the normalizing process are shot-blasted to break the oxide scale on their surface, followed by pickling. Pickling is carried out in three stages. The first stage uses a mixed solution of NH4HF2 and HCl, with an NH4HF2 concentration of 80 g / L and an HCl concentration of 155 g / L. The pickling temperature T5 is 98℃, and the pickling time t is 38 s. The second stage uses the same mixed solution, with an NH4HF2 concentration of 80 g / L and an HCl concentration of 200 g / L. The pickling temperature T5 is 92℃, and the pickling time t is 28 s. The third stage uses a mixed solution of H2O2 and HCl, with an H2O2 concentration of 50 g / L and an HCl concentration of 120 g / L. The pickling temperature T5 is 85℃, and the pickling time t is 50 s.

[0160] (6) Cold rolling

[0161] A 20-roll single-stand reciprocating cold rolling process was used to process the hot-rolled strip after pickling to obtain a cold-rolled coil with a thickness of 0.35 mm. The reduction rate of the first pass was controlled at 35%, and the total reduction rate was controlled at 80.5%.

[0162] (7) Annealing

[0163] The cold-rolled coils obtained from the cold rolling process are sent to an annealing furnace and subjected to high-temperature annealing under a pure N2 protective atmosphere. The annealing temperature is T6 = 1022℃ and the annealing time is 100s. The steel coils after high-temperature annealing are controlled to complete full recrystallization and the average grain size is 100μm. During cooling, the cooling rate is controlled to be ≤10℃ / s before cooling to 400~550℃.

[0164] (8) Coating

[0165] An insulating layer is uniformly coated on the upper and lower surfaces of the annealed non-oriented silicon steel strip and then finished to obtain a high-Si, high-Al non-oriented silicon steel product.

[0166] The non-oriented silicon steel products from the three embodiments were tested to obtain their iron loss P. 1.5 / 50 Iron loss P 1.0 / 400 Iron loss P 1.0 / 800 Magnetic induction intensity B 2500 and magnetic induction intensity B 5000 The data is shown in Table 2.

[0167] Table 2

[0168]

[0169] As can be seen from the table above, the high-Si, high-Al non-oriented silicon steels of Examples 1-3 have excellent magnetic properties.

[0170] In addition, the surface quality of the high-Si and high-Al non-oriented silicon steels in Examples 1 to 3 is qualified, and their magnetic properties are excellent, which can greatly meet the needs of high-efficiency and energy-saving motors. Moreover, no cracks occurred during the preparation of the winding core.

[0171] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0172] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing a high-Si high-Al non-oriented silicon steel, characterized by, The process comprises sequentially smelting, continuous casting, hot rolling, normalizing, pickling, cold rolling, annealing and coating processes; In the smelting process, the chemical composition of the smelted final molten steel includes, in mass percentage: C≤0.0025%, Si 2.0-3.5%, Al 1.0-2.0%, Mn 0.2-0.4%, Nb≤0.002%, V≤0.002%, Ti≤0.002%, Ni≤0.03%, Cr≤0.03%, Cu≤0.01%, N≤0.002%, P≤0.01%, S≤0.0015%, and Sn or Sb, with the rest being Fe and inevitable impurities, wherein the content of Sn is 0.01×Si+0.04×Al, the content of Sb is 0.01×Si+0.04×Al, and C+S+O+N≤0.007%; In the continuous casting process, a special protective slag is used for the continuous casting crystallizer, and the chemical composition of the protective slag includes, in mass percentage: SiO2 28-36%, MgO≤5%, CaO 16-24%, Fe2O3≤5%, Al2O3≤5%, Na2O 13-15%, CaF8-14%, Li2O 1.1-1.5%, B2O3 4.5-5.5%, T.C≤1.5%, and a heat generating agent 1.9-2.1%. In the hot rolling process, the continuous casting billet obtained in the continuous casting process is sequentially subjected to heating, rough rolling, finish rolling and coiling to obtain a hot-rolled coil, the heating temperature T1=1160-20×[Si]-10×[Al], the heating time is 160-180 min, the finish rolling temperature T2=880-20×[Si]-15×[Al], and the coiling temperature T3=600+5×[Si]-30×[Al]; In the normalizing process, the uncoiled strip steel is heated by non-oxidizing open flame, the heating rate of the strip steel is 30-40℃ / s, the soaking temperature T4=1050-30×[Si]-20×[Al], the soaking time in the soaking section is 40-70 s, then slow cooling to 700℃, the cooling rate during slow cooling is 10℃ / s, then fast cooling to room temperature, and the cooling rate during fast cooling is 30℃ / s; In the pickling process, pickling is carried out in three stages, the first stage uses NH4HF2+HCl mixed solution, the concentration of NH4HF2 is 60-80 g / L, and the concentration of HCl is 150-200 g / L; the second stage uses NH4HF2+HCl mixed solution, the concentration of NH4HF2 is 80-100 g / L, and the concentration of HCl is 200-250 g / L; the third stage uses H2O2+HCl mixed solution, the concentration of H2O2 is 30-50 g / L, and the concentration of HCl is 100-120 g / L; the pickling time t and the pickling temperature T5 of the three stages correspond to each other and satisfy: where B = -0.01 x [NH4HF2] 2 + 2 x [HC1] - 75, t is in s, and temperature is in °C.

2. The production method of high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, In the continuous casting process, the heat generating agent is calcium-silicon alloy, wherein the mass percentage of Ca is 40%, and the mass percentage of Si is 60%.

3. The production method of high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, The binary basicity of the protective slag is 0.61-0.63, the melting point is 1000±40℃, and the viscosity is 0.2±0.05 Pa·s.

4. The production method of high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, In the continuous casting process, electromagnetic stirring is used in the secondary cooling zone, the stirring current is 400 A, the stirring frequency is 8 Hz, and the continuous casting speed is 1.2±0.1 m / min.

5. The production method of high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, In the cold rolling process, the hot rolled strip after the pickling process is reciprocally cold rolled by a twenty-roll single-stand, and a cold hard coil with a thickness of 0.2-0.4 mm is obtained, the reduction of the first pass is controlled to be 25-35%, and the total reduction is controlled to be 80-90%.

6. The production method of high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, In the annealing process, the cold hard coil obtained in the cold rolling process is high-temperature annealed under a pure N2 protective atmosphere, the annealing temperature T6=900+30×[Si]+20×[Al] (unit: ℃), the annealing time is 80-100 s, the steel coil after high-temperature annealing is controlled to complete full recrystallization, and the average grain size is 80-120 μm.

7. The method of producing a high-Si high-Al non-oriented silicon steel according to claim 6, characterized by, In the annealing process, the steel coil after high-temperature annealing is cooled, and the cooling speed before cooling to 400-550℃ is controlled to be ≤10℃ / s.

8. The method of producing a high-Si high-Al non-oriented silicon steel according to claim 1, characterized by, In the hot rolling process, the continuous casting billet is sent into a heating furnace for heating, the billet entry temperature is 500-600℃, rough rolling is performed by double-stand in 6 passes, including 1 pass in the first stand and 5 passes in the second stand, and the total reduction of the seven-stand finishing mill is controlled to be 93-94%, and the thickness of the hot rolled coil is 1.8-2.0 mm.

9. A high Si high Al non-oriented silicon steel, characterized in that, The high-Si high-Al non-oriented silicon steel is prepared by the production method of any one of claims 1-8. The high-Si high-Al non-oriented silicon steel is prepared by the production method of any one of claims 1-8.

10. The high-Si high-Al non-oriented silicon steel according to claim 9, characterized in that, Its iron loss P 1.5 / 50 ≤2.5W / kg, iron loss P 1.0 / 400 ≤17W / kg, iron loss P 1.0 / 800 ≤25W / kg, magnetic induction B 2500 ≥1.58T, B 5000 ≥1.63T.

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